Posts Tagged ‘colour-correction’

Fix It In Post available for pre-order…

Fix It In Post coverMy latest book, “Fix It In Post” is available for pre-order now on Amazon.

Thanks to everyone who let me pick their brains over the course of the last few months.

The blurb:

“Finally!  A well-written software agnostic guide to fixing common problems in post ranging from shaky camera to film look!”

—Jerry Hofmann, Apple Certified Trainer; FCP Forum Leader, Creative Cow; Owner, JLH Productions

Fix It In Post provides an array of concise solutions to the wide variety of problems encountered in the post process. With an application-agnostic approach, it gives proven, step-by-step methods to solving the most frequent postproduction problems. Also included is access to a free companion website, featuring application-specific resolutions to the problems presented, with fixes for working in Apple’s Final Cut Studio suite, Avid’s Media Composer, Adobe Premiere Pro, as well as other applications.

Solutions are provided for common audio, video, digital, editorial, color, timing and compositing problems, such as, but not limited to:
* automated dialogue recording, adjusting sync, and creating surround sound
* turning SD into HD (and vice-versa) and restoration of damaged film and video
* removing duplicate frames, reducing noise, and anti-aliasing
* maintaining continuity, creating customized transitions, and troubleshooting timecodes
* removing vignettes, color casts, and lens flare
* speeding shots up, slowing shots down, and getting great-looking timelapse shots
* turning day into night, replacing skies and logos and changing camera motion

Fix It in Post: Solutions for Postproduction Problems

Snow Leopard to change default gamma…

From the release notes of the beta of Mac OS 10.6 (“Snow Leopard”):

Default Gamma Changes

To better meet the needs of digital content producers and consumers, the default display gamma has been changed from 1.8 to 2.2 in Snow Leopard.

This will be a welcome change to anyone who has run into cross-platform issues with gamma.

Posted: January 20th, 2009
Categories: News
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Dithered Colour Correction for 4k and Beyond…

This is how digital colour correction works:

If you change the brightness for any part of the image, all the selected pixels are affected in the same way.

In one of my previous rants, I proposed that resolution was more important than bit-depth… Since then, I’ve been wondering why, in practice, this is never the case. After some thought, I realised that the way digital colour correction works is different from changing the exposure of film.

Changing the exposure of film, on microscopic level, affects the image like this:

The individual grains are not affected uniformly. It’s that a percentage of the grains become exposed (or not), not that every grain becomes more exposed. To the viewer, the result from a distance is that the affected region is brighter. It’s also the reason that grain structures are visible.

Until now, it didn’t make sense for colour correction software to work like this: the resolution of images was too small to make sense. However, for 4k and beyond, non-uniform (or dithered) colour-correction may very well yield superior control over the colour-correction process.

So the question I find myself asking is, why don’t any high-end colour grading systems offer this kind of functionality?

Posted: April 19th, 2008
Categories: Articles
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Photoshop’s Weakness…

I’m a big fan of Photoshop. Well, I was a fan of LivePicture first, before that went bust, and when Photoshop first became popular, I preferred Corel PhotoPaint much more, but whenever it was they added multiple levels of undo (well, some roundabout implementation of undo, at least) I made the switch, and never looked back. I loved when they added blending modes– something I think all grading systems could use, and then again with the introduction of adjustment layers. Finally it was turning into a tool that could work in a non-destructive manner.

Apparently there’s a beta version of Photoshop CS4 that’s been leaked… recently, but I’ve not read anything that suggests what’s going to be in the next version. Given that the last few releases have mainly focused on workflow improvements, it almost feels like there’s nothing more to be done with it.

Today I was doing some pre-viz with a colorist, who was explaining to me that he found it very frustrating to try and correct images with Photoshop’s toolset, that it was much more intuitive to use Baselight even just to work with stills. Surely that can’t be right, I thought. Photoshop has been used, probably by millions of people, to accomplish all sorts of wonderful colour changes.

So I went off to try and replicate a Baselight-eque workflow in Photoshop. After a few hours, I realised that it can’t be done. Now, that’s not to say that you can do stuff in Baselight that you can’t do in Photoshop, but it absolutely means you can’t work the same way. For overall changes, there’s no difference between the two: you can use adjustment layers stacked on top of each other in Photoshop to allow non-destructive colour-correction. But secondaries are a different story. It boils down to this: Photoshop’s implementation of vectors is horrible.

Really, really horrible. In Baselight (as well as many other grading systems), you’d do something like this: create a shape/mask, add some softness, adjust the colour within the shape, then tweak, tweak, tweak. The closest analogue in Photoshop that I’ve found, is to create an adjustment layer, then use the pen tool or one of the shape tools to create the shape(s). You can then go ahead and modify the adjustment layer to your liking.


Because of the way Photoshop is designed, you can tweak this in a lot of ways that you probably couldn’t in a grading system. For instance, you can change the blending mode and opacity of the  adjustment layer- effectively giving you control of the overall effect. You can paint on the adjustment layer too, easily combining vectors and pixel-based masked in a single correction.

But none of that changes the fact that Photoshop’s vector tools are really bad. I don’t just mean the way the user interface works (although even that is really awful, given the vast number of applications out there which are able to make bezier curve editing effortless), but I mean that they seem like an afterthought. For instance, there is apparently no way to alter the softness of the edge of a shape, without rasterizing it first, at which point you can blur it or whatever to get the desired effect. However, there’s are good reasons that grading systems don’t work this way (aside from the fact we’re working with moving pictures, of course), which are that it’s a destructive process, and it’s much slower (for the user).

lustre-25-Selective_large.jpg (JPEG Image, 700×438 pixels)

It’s so clear to me now– Photoshop wants you to work with pixels, not shapes. I can understand that, after all, where you would draw a shape around a balloon in Baselight, in the ‘Shop you could just isolate the balloon onto it’s own layer, and then just tweak that layer to your heart’s content, which theoretically will allow you to create much more accurate masks. You can save every mask you create as a pixel-based alpha channel, so you still have the ability to isolate it again if you want. But there’s the pitfall– if you do something to break the balloon layer, you have to go back to square one in a lot of cases. If you blur (or feather) a selection just a little too much, and don’t realise until it’s too late, then you have to start over (unless you had the foresight to save a copy of the layer just before you feathered it).

The vector tools are clearly there for other reasons, and are not meant for doing the sort of things they’re used for in grading systems, and that seems like a real shame, because in combination with the rest of the toolset, they could be very powerful. But then Photoshop’s not supposed to be a vector-based application. It’s not built to replicate the workflow of a Baselight system, and maybe it doesn’t need to be. But more than that, it seems that it’s just not built for speed.

Posted: March 26th, 2008
Categories: Tools
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Apical Imaging’s Real-time Colour Corrector…

As much as I don’t like push-button colour-correction boxes as a rule, I’ve also seen enough live television to understand the need for them. Live broadcasts tend to have little (if any) thought to colour given to them beyond the parameters the camera operator set when she first switched the camera on. The problem with real-time colour-correctors is that they tend to correct the overall brightness and contrast of an image, without any consideration for the dynamic range. The result of this is that scenes with strong backlighting can look dark, or that highlights and shadows can look muddy.

Apical’s box, the D-Rex LCP-100, is different in this regard. Developed in conjunction with Fuji TV and Storenet, the unit uses their Iridix image processor to separate a live HDSDI stream into shadows, highlights and midtones, and correct them independently, with some noise reduction thrown in for good measure. I had the opportunity to see a demo of the box in action, and the results were very promising, even with a minimal amount of user configuration.

It doesn’t appear to be on sale yet, but the technology has been available on a number of devices for a while, from Sony’s Alpha series SLRs to The Foundry’s Furnace plugins.

Posted: February 29th, 2008
Categories: Tools
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